Many application programs provide video output, e.g. display of images on a computer monitor, during execution. Such video output is controlled, in part, by a video interface which includes a software module called a display driver and hardware component which connects to the monitor called a video card. The display driver receives requests from the application program and translates the requests into instructions that are understood by the video card. The video card executes the instructions, which process results in desired images being rendered and displayed on the monitor.
A frame is a static display of images on the monitor at a particular time. Animation, i.e. moving images, is achieved by rendering and displaying successive frames. Some application programs, such as certain games, rely heavily upon animation during execution. The performance of these applications programs on a computer system depends upon how well that system is able to display the desired animations while the application executes. This depends in large part on the quality of the video interface.
Video interfaces are rated using certain metrics. One example of a metric is a measured frames per second (FPS). The measured FPS is obtained by executing a benchmark, e.g. a portion of an application that uses video output, to determine how many frames are displayed over time. The number of frames displayed is divided by the benchmark execution time to arrive at the FPS value. Once measured, the FPS value is supposed to provide a comparative measure of the performance that will be achieved using a particular video interface. The larger the FPS value, the better the video interface is supposed to perform.
FPS does not, however, necessarily provide an accurate reflection of the relative performance that will be achieved in general. Video interface performance depends on many system resources, including the CPU and how efficiently the computer is used. Thus, the benchmark needs to simulate all possible scenarios of system resource utilization for the FPS to accurately represent the video performance that will be achieved with different computer systems. It is not practical, however, to design such a benchmark.